At present, in the field of organic light emitting devices and liquid crystal displays, organic functional thin films and colored films are typically formed using an inkjet printing process. An indispensable step in the inkjet printing process is to require subsequent procedures to remove excess solvent and then form a desirable film by drying. This solvent removal process determines morphology of the film. For an optoelectronic display device, morphology and uniformity of the dried film have a great impact on expected life of the device and display effect.